1. Technical Field
The present invention relates to a piezoelectric element for use as a liquid-ejecting head drive, such as an ink jet print head drive, and a method for manufacturing the piezoelectric element, a liquid-ejecting head and a method for manufacturing the liquid-ejecting head, and a liquid-ejecting apparatus. More particularly, the invention relates to a piezoelectric element that deforms as much as possible during startup and exhibits a small time-dependent decrease in deformation, and a method for manufacturing the piezoelectric element, a liquid-ejecting head and a method for manufacturing the liquid-ejecting head, and a liquid-ejecting apparatus.
2. Related Art
Liquid-ejecting apparatuses include a liquid-ejecting head and eject various liquids from the liquid-ejecting head. Representative liquid-ejecting apparatuses include image recorders, such as ink jet printers. Ink jet printers include an ink jet print head (hereinafter referred to simply as a print head) as a liquid-ejecting head and eject liquid ink from nozzle openings of the print head onto a recording medium (an ejection target), such as recording paper, to print images composed of dots. In recent years, in addition to the image recorders, liquid-ejecting apparatuses have been applied to various manufacturing apparatuses, such as apparatuses for manufacturing color filters for use in liquid crystal displays.
A drive for ejecting liquid in a liquid-ejecting head, that is, a piezoelectric element used as pressure-generating means for altering the pressure of liquid in a flow passage in a liquid-ejecting head, includes a piezoelectric film between electrodes. For example, the piezoelectric film is formed of a crystallized piezoelectric ceramic, more specifically, lead zirconium titanate (PZT) (see, for example, JP-A-2006-306709). The characteristics of the piezoelectric element depend on the composition of PZT. For example, it is known that the deformation of the piezoelectric element during startup (initial deformation) can be increased with an increase in titanium (Ti)/zirconium (Zr) ratio.
However, it is also known that an excessively high Ti/Zr ratio results in a high deformation reduction rate that depends on the number of operations performed. In contrast, a lower Ti/Zr ratio results in a smaller initial deformation during startup but a lower deformation reduction rate. Thus, there is a trade-off between a large initial deformation and a low deformation reduction rate, and it is difficult to realize both a large initial deformation and a low deformation reduction rate to a high degree.